One vaccine, many diseases: The study trying to find universal protection

A single vaccine to protect against several diseases would be convenient and according to one study it may also be possible.

Stanford University School of Medicine professor Dr Bali Pulendran is a senior author on the American experiment looking at a vaccine that could protect against the flu, Covid and other diseases.

He told Saturday Morning that the study was still in its early stages, but its aim was to deliver a wide range of protection.

"What the experiments show is that if you deliver this vaccine intranasally, it can induce immunity that seems to be remarkably broad in conferring protection against many different strains of viruses, different strains of bacteria, but also allergens."

So far, the vaccine was being administered through the nose on mice.

"It's administered through a pipette into the nostrils of mice and ultimately, we think that as we move forward into translation, that this could be a nasal spray that's administered to humans."

Pulendran added it was important that the vaccine be administered nasally.

"Because we were trying to protect against respiratory infections. And if you wish to evoke the kind of immune response in a tissue, in a local site, I think the best mode of delivery is through a route that's proximal to that site."

He said if successful, this would be helpful should we encounter another pandemic in the future that is more dangerous than Covid-19.

"So that's where I think this kind of universal vaccine that could be administered broadly to the population at the very earliest signs of the pandemic could be useful as a sort of a stopgap measure in imprinting immunity on a population-wide level for some period of time."

He said it could also be useful during non-pandemic times such as the flu season where it can be distributed as a nasal spray.

Historically the way vaccines worked was by teaching the immune system to respond to a bit of a pathogen.

Pulendran said for this immunisation the idea was to "integrate" the innate and adaptive immune system to launch a response that was "broad" and "pathogen agnostic".

The adaptive immune system was made of antibodies and T-cells. The innate immune system was something Pulendran referred to as evolutionarily "ancient" and was "broader" in its ability to protect against infections.

"Unlike the adaptive immune system, the innate immune system is not very specific. It's really quite broad."

"Regardless of the pathogen, whether it's a microbe or a virus or a fungi, the innate immune system can launch this incredibly broad response."

Although broad the innate immune system was not very "long lived", lasting only a few minutes or days, potentially weeks.

"The strategy that we came up with was to leverage the incredible breadth of the innate immune system, but the longevity of the adaptive immune system."

"So, we could allow the adaptive immune cells in the lungs to teach the innate immune system to keep going for far longer than just a few days or a few weeks and in this case, in mice, up to about six months or so."

He said mice that had been given the intranasal vaccine and later infected with bacteria, allergens and viruses such as SARS and some coronaviruses were protected for three or up to six months.

"What's happening now is that we are planning a study in humans where we could test this concept to see if this vaccine is safe and efficacious."

"If that proves to be successful, I think this would represent a remarkable departure from how we view vaccines."

Following the testing on mice the next step is a toxicology study on rabbits.

If the toxicology study produces positive results, Pulendran said they would look to do a "dose escalation study" in humans, a process they were fundraising for.

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